At present, as more and more people use Wireless Local Access Network (WLAN) to carry out data communication, WLAN network load increases constantly. The industrial specification group of Institute of Electrical and Electronic Engineers (IEEE802.11) successively defines a series of standards such as IEEE 802.11a/b/g/n/ac to meet the ever-increasing communication requirements. These standards are committed to improving the technology of 802.11 so as to increase the maximum physical layer transmission rate or maximum network throughput. However, as the number of users grows, the efficiency of the WLAN network has a trend to decrease dramatically, and purely increasing rate cannot solve a problem. Therefore, the working group sets up a relevant High Efficiency WLAN (HEW) group to work on solving the WLAN network efficiency problem.
In traditional WLAN systems, scheduling information may be indicated in a Signal (SIG) Field of a physical frame header. FIG. 1 shows physical frame formats of non-High Throughput (Non-HT) of IEEE802.11a and HT-mixed of IEEE802.11n. Herein, Legacy SIG (L-SIG) may bear the resource scheduling information of non-HT, mainly including a transmission rate and a transmission length. In the HT-mixed format, the scheduling information is expanded. Specifically, besides the L-SIG field, the HT-SIG also stores the scheduling information. Besides the transmission rate and the transmission length, indicator information related to Multiple Input Multiple Output (MIMO) is added, for example, whether it is sounding frame, number of layers, etc. In addition, indicators of new features of 802.11n are also added, for example, aggregation, Space Time Block Code (STBC), etc. FIG. 2 is a physical frame structure of IEEE 802.11ac. Since the downlink Multi-User Multiple Input Multiple Output (MU-MIMO) technology is supported, the scheduling information may be expanded. Therefore, the frame format Very High Throughput SIG (VHT-SIG) of 802.11ac may be divided into two parts: VHT-SIG-A and VHT-SIG-B which respectively bear different information. In 802.11ac, single-user and multi-user may adopt the same resource indicator overhead, and some bit positions may respectively have different syntaxes in the case of single-user and multi-user.
The L-SIG, HT-SIG and VHT-SIG-A may be repeatedly transmitted with 20 MHz as a unit. The VHT-SIG-B is not repeatedly transmitted with 20 MHz as a unit; however, depending on different bandwidths supported, the content that can be carried by 20 MHz first may be bit-level repeated and then may be subjected to subsequent code modulation mapping processing during transmission.
Traditional WLAN may only support full-bandwidth scheduling users. However, in actual application, there may be a high proportion of small data packets, and the transmission of small data packets using a large bandwidth may need a great overhead. In addition, the frequency selective fading of large bandwidth may have a much higher probability than small bandwidth. Considering the above factors, a next generation of WLAN technology introduces an Orthogonal Frequency Division Multiple Access (OFDMA) manner to realize the requirements of transmitting small data packets using a small bandwidth and selecting partial bandwidth according to a frequency selective result.
In the OFDMA technology, frequency resources of one same time period may be allocated to multiple users, and scheduling information may be needed to indicate the resource of each user. Taking a resource allocation granularity of 5 MHz for example, 160 MHz may support at most 32 users. If the scheduling information (also called scheduling indicator information) of all the users is transmitted on the main channel and repeated on other secondary channels according to a traditional manner, the transmission may last for a long time and great resource waste may be caused.
At present, scheduling information may be divided into two types: public scheduling information (which is called navigation information or HE-SIG-A in the solution) and scheduled user specific information (which is called user specific information, or HE-SIG-B). The public information may be repeatedly transmitted on an available frequency band currently scheduled, with a 20 MHz frequency band as a unit, similar to traditional WLAN technologies. However, there is no complete efficient solution for the method on how the public information (e.g., public scheduling information) indicates a receiving end to parse the user specific information so far.
In view of a problem of how the public information indicates a receiving end to parse the user specific information, no effective solution has been proposed so far.